This invention relates generally to electrical power distribution equipment and particularly to a ground fault adapter for providing ground fault protection for a circuit breaker panel. Circuit arrangements for protecting against ground fault currents are well known in the art. One prior art device manufactured by Square D Company is a two pole circuit breaker with built-in ground fault detection comprising a magnetic toroid having a window through which the phase and neutral wires are passed. The neutral wire from the breaker is connected to an earth ground. Any unbalanced current flow in the wires passing through the toroid window is sensed by a sensing winding on the toroid and, if in excess of a threshold value, fires an SCR to connect a trip coil across one of the phases to ground. The trip coil operates a plunger that mechanically trips its associated pole of the breaker. The arrangement includes a pair of trip coils with one each being connected to a phase of the load circuit. The breaker poles are mechanically interconnected so that tripping of one pole results in tripping of the other pole. The two trip coils are provided to insure that tripping occurs in the event of a fault, even if one of the phases is de-energized. There is a perceived need for a ground fault protection device as an accessory for standard circuit breakers.